Offset driving tool



Jan. 26, 1965 s. DOWNS, JR 3,166,757

OFFSET DRIVING TOOL Filed Jan. 8, 1962 INVENTOR HUEBNER 8 WORREL UnitedStates Patent 3,166,757 @FFSET BRTVBNG T601 Samuel Downs, .lru, Fresno,Caliil, assignor of twentysc-ven percent each to Harold Zinlrin, GilbertH. Bragg,

and Wiley J. Thompson, md nineteen percent to Dr.

Charles H. lass, all of Fresno, Calif.

Filed .lan. 8, 1962, Ser. N 164,793 8 Claims. ((Il. 1-47) The presentinvention relates to an offset drlving tool adapted to transmit adriving force at a point remote from and in offset relation to anapplied force. The present invention particularly relates to a drivingtool adapted to transmit the kinetic energy resulting from impact by afirst object, such as a hammer, to a second object laterally offset fromthe first, wherein the resulting mechanical vibrations of the drivingtool are to be minimized.

The present application is a continuation-impart of application SerialNo. 48,475, filed August 9, 1960, now abandoned.

The tool of the present invention has particular utility in the field oflaying wall-to-wall carpeting. it is extremely useful when suchcarpeting is overlaid a floor composed of a hard brittle substance, suchas concrete or terrazzo, into which nails are to be driven. it is acommon practice in this field to nail to the floor a Wooden strip inwhich are embedded upwardly presented carpet retention tacks. Thesestrips are placed against the walls, or the baseboards therealong, andare subsequently overlaid by the edges of the carpet which are securedin place by the upwardly presented tacks. In the laying of carpet, it isnecessary to secure such tack strips substantially continuously aboutthe peripheral edges of the door and under any overhanging obstructionthat may be mounted on the circumscribing walls. A variety of objects inthe average home and ofiice cornprise such obstructions and theygenerally protrude outwardly from the wall in relatively closelyupwardly spaced relation to the floor. Accordingly, it is impossible todrive a nail through a tack strip under such an obstruction by using adirect blow from a hammer.

Previous tools, which have been employed unsuccess fully in drivingnails under such obstructions without first removing the obstruction,include conventional crowbars and other levers of varying configurationand cross-section. Levers in the cross-sectional configuration of an I-beam have also been employed wi hout a marked degree of success. Theusual problem is that the tool is either too resil ent or too rigid.Consequently, the force imparted to the nail is either insufiicient todrive the nail into a concrete floor or the natural frequency of vibration of the tool is such that the nail is vibrated and consequentlyloosened in the hole formed in the concrete incident to the nail beingdriven into the floor. Other undesirable characteristics of such toolsare the stinging mechanical vibrations transmitted to the hands ofworkmen employing the tools as well as audible ringing sounds producedwhen such tools are struck with a hammer.

Accordingly, it is an object of the present invention to provide animproved offset driving tool.

Another object is to provide an offset driving too! with silientmaterial, with an insulative covering capable of damping the vibrationsof such a tool when struck during use.

object is to provide a steel alloy specifically These, together withother objects, will become more fully apparent upon reference to thefollowing description and accompanying drawing.

in the drawing:

FIG. 1 is a side elevation of the offset driving tool embodying theprinciples of the present invention.

FIG. 2 is a bottom plan view of the tool.

FIG. 3 is a vertical section of a wall and a concrete floor on which itis desired to lay wall-to-wall carpeting and a side elevation ofthe-subject tool as employed in securing a tack strip to the floorbeneath an overhanging obstruction borne by the Wall.

FIG. 4 is a transverse, vertical section taken on line 4-4 of FIG. 1.

PK}. 5 is a view in side elevation of a modified form of the tool of thepresent invention.

As shown in FIG. 1, an offset driving tool embodying the principles ofthe present invention includes a body member it which is ofsubstantially triangular configuration when viewed in side elevationintegrally joined to the body member is a handle ll. An upwardlypresented anvil portion 12 is disposed intermediate a driving endportion 13 and a fulcrum end portion 14 adjacent to the handle 11. Aninterconnecting web 15 joins the anvil with the driving and fulcrum endportions. The web is provided with tapering side surfaces 316 whichterminate in a base edge 17. As viewed in FIG. 4, the

ch in cross-section is in the form of an inverted triangle in which thebase is relatively short in relation to the height. The base and heightare so proportioned to minimize the overall weight of the tool and toprovide the Web with the proper degree of elasticity so that the toolwill not rebound from the nail when struck a blow during use. Asatisfactory proportion between the base and hei ht results by using adimension of .75 inch for the base and a dimension of 1.75 inches forthe height as indicated in PEG. 4. The anvil portion 12 is superimposedover the base of the inverted triangularly shaped Web and projectslaterally to provide an upwardly presented striking area larger thanthat afforded by the web 15. p

The body member 19 terminates at the fulcrum end portion 14 in adownwardly presented fulcrum 20. The fulcrum is provided with asubstantially convex surface to permit rocking movement of the toolabout the fulcrum in a counterclockwise direction as viewed in FIG. 1.

The body member 1% is provided with a driving head 3%) remote from an inoffset relation to the fulcrum 2%). The driving head includes adownwardly presented work engaging surface 31 which is tapered from aleading edge 32 remote from the fulcrum to a trailing edge 33.. With theabove proportionate web dimensions, a satisfactory distance between thefulcrum 2t and the leading edge 32 has been found to be twelve inches.The anvil portion is located intermediate the leading edge and thefulcrum at a point substantially equidistantly spaced from these endportions.

The handle 11 includes a pair of legs ill integrally joined with acentral-portion 41, to result in a closed type of handle. Thisconstruction precludes any portion of the handle from vibrating freelywhen the tool is struck a driving blow. To minimize the transmission ofsuch vibrations to the hand of a workman employing the tool, the handleis substantially encased with an insulative cover C. The cover is formedof a resilient material having desirable vibration damping characteristics. Materials such as natural and synthetic rubber and imperviousplastics, such as vinyl, have been employed successfully.

f The relative locations of the anvil 12, the driving head fill, thefulcrum 2b, the distribution. of. mass of the body member lb, and thehandle it are such to result in a center of gravity located within theweb member at a adapted for casting the tool in the form shown.

. point intermediate the anvil and the fulcrum but nearer to the' anvil.As shown in FIG. 1, the center of gravity is located at a pointapproxhnately forty percent of the distance from the fulcrum to thedriving head portion. It is to be noted also that the fulcrum Zil, thecenter of gravity, and the anvil portion 12 are substantially in alignment. This results in a balanced construction, the significance of whichwill be discussed below.

In FIG. 5, a second form of the tool is shown of substantially thesameconliguration as that of the tool shown in FIG. 1 except that thetool is substantially encased in an insulative cover C. Only the workengaging surface 31, the anvil portion 12 and the downwardly presentedfulcrum 20 are exposed, while the remaining surfaces are insulated bythe cover C. With the second form, a maximum surface area is coveredwith a vibration damping material.

The tool is formed of a metal having suthcient rigidity to transmit adriving blow of significant force, but the metal must be of a characterhaving little resilience or springiness. In addition, the tool must beof a sufficiently tough material and not brittle so as to be likely tobreak during use. These characteristics are quite significant and briefreference is made to the composition of the preferred materialspecifically developed for the tool and The body and integral handle ispreferably made of a cast steel alloy having an optimum composition asfollows:

Carbon 25%. Manganese 1.00 to 1.50%. Silicon 60% maximum, Chromium .50to 1.00%. Molybdenum .30 to 50%. Vanadium .08 to .l2%.

Balance consisting essentially of iron.

'Number 325 to 375.

Operation The operation of the described embodiment of the subjectinvention is believed to be readily apparent and is briefly summarizedat this point. As an aid to describing the operation of the subjecttool, reference is made to its environment of use. As illustrated inFIG. 3, a wall 42 is upwardly extended from a floor 43 having an uppersurface 44. Since severe vibration problems are encountered when drivingnails into concrete floors, it is to be understood that the floor 43 isof a concrete material. A wall heater 46, typifying one of several typesof overhanging obstructions, is mounted on the wall and has a lowersurface 47 upwardly spaced from the upper surface of the floor. Abaseboard 48 is secured to the wall adjacent to the upper surface of thefloor and in a conventional manner.

The subject tool is used when it is desired to secure a tack strip 59 tothe floor 43 underneath a wall heater 46, or other overhangingobstruction. In actual use, the tack strip is positioned on the uppersurface 44 of the floor under the lower surface 47 of the wall heater, anail 52 is positioned on the strip, and the driving end portion 13 ofthe tool is extended under the wall heater and over the nail. With theconvex surface of the fulcrum member 2!) rested on the floor in alaterally outwardly spaced relation to the wall heater, the workengaging surface 31 of the driving head is rested on the head of thenail. It is evident that the anvil portion 12 of the body is upwardlydisposed and outwardly spaced from the wall heater. It is also evident,as illustrated in FIG. 3, that the handle ll is spaced outwardly fromthe wall heater on the opposite side of the anvil portion from theheater.

With the tool proportioned as above, the work engaging surface 31 istapered from the leading edge 32 to the trailing edge 33. As shown inPEG. l, this taper provides an acute angular relationship between thesurface 31 and a plane surface on which the tool is supported by theleading edge 32 and the fulcrum 2d. The angle of such relationship issuch that the tangent of the angle is substantially equal to thepredetermined length of the nail 52 divided by the distance between theleading edge 52 and the fulcrum it This distance is twelve inches in theparticular tool illustrated; the nail length is five-eighths of an inch;and the angle of relationship between the work engaging surface 31 andthe plane surface represented by the floor 43 in PEG. 1 is 3.Accordingly, the tangent of 3 is substantially equal to .625+l2; or.0524 is substantially equal to .0521. The significance of such arelationship is shown in PEG. 3 with the nail in a position to be drivenby the tool. It is to be noted that the work engaging surface issubstantially normal to the longitudinal axis of the nail which insuresthe proper initial penetration of the nail into the floor 43. This isextremely important with concrete floors into which are driven hardenedsteel na ls having a circular cross-section and a pointed penetratingtip. in such an environment, it is imperative that th nail be startedproperly to avoid chipping of the floor, which would preclude anyretention of the nail.

The nail 52 is driven through the tack strip 5t! into the concrete floor43 by striking the anvil portion 12 with a hammer 55 as illustrated inFIG. 3. The kinetic energy of the hammer is consequently transmitted bythe body member 10 of the tool through the web 5 to the work engagingsurface 31 of the driving head 39. In transmitting this energy, the tooloperates in the nature of a third class lever in that the operatingforce is ap plied at a point intermediate the fulcrum and the load.Accordingly, the force available to efiect driving of the nail 52 issomewhat less at the work engaging surface 31 than the force transmittedto the anvil portion of the tool.

It is also to be noted that the distribution of mass of the tool is suchthat the center of gravity is located in the Web portion at a pointintermediate the anvil and the fulcrum. As stated above, the anvil,fulcrum, and center of gravity are also in substantial alignment.Accordingly, when the anvil portion is struck, a short lever arm isprovided for the striking force to act upon in relation to the center ofgravity. This results in a tendency to rotate the tool about the centerof gravity in a counterclockwise direction as viewed in FIG. 1. Sincethis is the same direction of rotation, or rocking movement of the tool,about the fulcrum 2%, internal stresses are minimized which greatlyreduce the mechanical vibrations which would otherwise be induced in thebody member it upon being struck by the hammer. Stated differently, thedriving tool constitutes a third class lever adapted to transmit uponimpact at the anvil portion a shock force to the driving head whereinthe anvil portion is located intermediate the fulcrum and the drivinghead, the center of gravity of the lever is located intermediate theanvil and the fulcrum all of which are in substantial alignment, and theanvil portion is located substantially coincident with the center ofpercussion of the lever whereby internal stresses are minimized when theanvil is struck. In addition, the steel alloy comprising the body memberis of a composition having excellent vibration damping characteristics.Therefore, vibrations resulting from the hammer blow are also minimizedby the particular steel alloy utilized in casting the tool.

Althoughthe tool as a substantially rigid metallic object, will have anatural frequency of vibration upon being stimulated by a blow, theobjectionable mechanical vibrations made to the hand of a workman areeffectively dampened by the insulative cover indicated at C and shown inFIG. 1 as substantially encasing the handle 11. Since the handle is of aclosed form having spaced legs integral with the body member and coveredby a resilient material such as natural or synthetic rubber or aplastic, such as vinyl, no portion of the tool is readily available totransmit sonievibrations to the surrounding air. If it were not for theparticular steel alloy and the configuration of the tool, the tool wouldresult in a ringing sound within the audible range of humans. However,with the tool of the present invention, thisaudible sound is minimizedand further prevented from being transmitted to the air through thevibration damping characteristics of the insulative material C.

As shown in the second form, the tool may be substantially totallyencased by such an insulative cover to preclude the possibility of anyobjectionable audible ringing sound from being produced during use ofthe tool.

The extremely low modulus of resiliency of the steel alloy used in thetool and the damping characteristics of the alloy minimizes anyvibration likely to be transmitted to the nail. Since nails driven intoconcrete floors may be loosened easily by vibrations transmitted to themby a working tool, it is imperative that any tool utilized in rivingsuch nails have a minimum of vibration. .In addition, the relationshipof the Work engaging surface and the fulcrum, when in an operativeposition, insure proper penetration of the nail.

From the foregoing, it will be evident that an improved offset drivingtool has been provided which is extremely useful in such an environment.The tool also facilitates driving nails, tacks, and other fasteners, inareas where the direct use of a hammer is precluded or rendereddifficult. The tool also enables application of driving force adjacentto objects which are easily damaged or broken.

Although the invention has been herein shown and described in what isconceived to be the most practical and preferred embodiments, it isrecognized that departures may be made therefrom within the scope of theinvention, which is not to be limited to the details disclosed hereinbut is to be accorded the full scope of the claims so as to embrace anyand all equivalent devices and apparatus.

Having described my invention, what I claim as new and desire to secureby Letters Patent is:

1. An offset driving tool comprising an elongated body member ofgenerally triangular configuration viewed in side elevation and havingoppositely extended driving and fulcrum end portions, a driving headdownwardly extended from the driving end portion and having a downwardlypresented face, a fulcrum downwardly extended from the fulcrum endportion, an upwardly presented anvil portion intermediate the drivingand fulcrum ends, and a web downwardly extended from the anvil portionto a base edge and extended toward the opposite end portions in atriangular configuration in side elevation, the web also beingtriangular in cross-section in a transverse vertical plane passingthrough the anvil portion, the triangular cross-section being ofinverted form and tapering toward the base edge, and an upwardlypresented closed handle portion integrally joined with the body memberat a point adjacent to the fulcrum end, the distribution of mass of thetool being such to locate the center of gravity thereof within the webat a point intermediate the anvil portion and the fulcrum end portion.

2. An offset driving tool comprising an elongated body member ofgenerally triangular configuration viewed in side elevation and havingoppositely extended driving and fulcrum end portions, a driving headdownwardly extended from the driving end portion and having a downwardlypresented face, a fulcrum downwardly extended from the fulcrum endportion, an upwardly presented anvil portion intermediate andsubstantially equidistantly spaced from the driving and fulcrum ends,and a web downwardly extended from the anvil portion to a base edge andextended toward the opposite end portions in a triangular configurationin side elevation, the web also being triangular in cross-section in atransverse vertical plane passing through the anvil portion, thetriangular cross-section being of inverted form and tapering toward thebase edge, and an. upwardly presented closed handle portion integrallyjoined with the body member at a joint adjacent to the fulcrum end, thedistribution of mass of the tool being such to locate the center ofgravity thereof within the web at a point adjacent to the anvil portionand intermediate the anvil portion and the fulcrum end portion.

3. The tool of claim 2 wherein the body member and the handle portionsare formed of a metal capable of producing mechanical and sonicvibrations when struck, and the handle portion is covered with avibration damping material whereby the sonic vibrations within the humanhearing range are substantially reduced and whereby the mechanicalvibrations of the handle are confined to said damping material.

4. The tool of claim 2 wherein the body member and the handle portionare formed of a cast steel having a predetermined natural frequency ofvibration normally capable of producing audible sounds when vibrated atsaid frequency and said body member and handle portion are substantiallyenclosed with a vibration damping material except for said driving headface, said fulcrum and said anvil portion whereby the vibrations of saidtool are substantially confined to said damping material.

5. An offset driving tool adapted for driving nails of a predeterminedlength and comprising an elongated body member of generally triangularconfiguration viewed in side elevation and having oppositely extendeddriving and fulcrum end portions, a driving head downwardly extendedfrom the driving end portion and having a downwardly presented face, afulcrum downwardly extended from the fulcrum end portion at apredetermined distance from the driving head, an upwardly presentedanvil portion intermediate the driving and fulcrum ends, said drivinghead face having a work engaging surface tapering away from a leadingedge remote from said fulcrum and in slight acute angular relationshipto a plane surface supporting the tool by said leading edge and fulcrum,the angle of such relationship being such that its tangent issubstantially equal to said predetermined nail length divided by thedistance between said fulcrum and said leading edge, and a webdownwardly extended from the anvil portion to a base edge and extendedbetween the opposite end portions, and an up wardly presented handleintegrally joined with the body member at a po nt adjacent to thefulcrum end, the distribution of mass of the tool being such to locatethe center of gravity thereof within the web at a point adja centto theanvil portion and intermediate the anvil portion and the fulcrum endportion.

6. An offset driving tool comprising an elongated body having oppositeend portions providing respectively a driving head and a fulcrum andhaving an anvil portion located intermediate said driving head andfulcrum, said anvil, head and fulcrum being arranged in the nature of athird class lever, the distribution of mass of the tool being such thatthe center of gravity of the tool is located intermediate the anvil andthe fulcrum, the respective locations of the anvil, the fulcrum and thecenter of gravity being such that all are in substantial alignment, andthe anvil portion is located substantially coincident with the center ofpercussion of the tool whereby internal stresses and vibrations of thetool are minimized when the anvil is struck.

7. An offset driving tool comprising an elongated body having oppositeend portions providing respectively a driving head and a fulcrum andhaving an anvil portion located intermediate said driving head andfulcrum, the distribution of mass of the tool being such to have acenter of percussion located intermediate said driving head and thefulcrum, the distribution of the mass of the tool also disposing thecenter of gravity of the .tool intermediate the center of percussion andthe fulcrum in substantial alignment therewith so'that internal stressesand vibrations of the tool are minimized when the tool is struck.

8. An offset driving tool comprising an elongated body having oppositeend portions providing respectively a driving head and a fulcrum andhaving an anvil portion located intermediate said driving head andfulcrum, the distribution of mass of the tool being such to have acenter of percussion located intermediate said driving head and thefulcrum, the distribution of the mass of the tool also disposing thecenter of gravity of the tool intermediate the center of percussion andthe fulcrum with said center of gravity, said center of percussion andsaid fulcrum being disposed in spaced relation in a common plane so thatinternal stresses and vibrations of the tool are minimized when the toolis struck.

References Cited in the file of this patent UNITED STATES PATENTS266,834 Johnston Get. 31, 1882 1,280,549 Reynolds Oct. 1, 1918 1,410,861Erickson Mar. 28, 1922 1,495,092 Malrowski May 29, 1924 2,577,954 Di'Pie-tro Dec. 11, 1951 2,837,421 Kron lune 3, 1958 2,949,355 DyrliaczAug. 16, 1960 2,968,810 Young et ai Jan. 24, 1961

1. AN OFFSET DRIVING TOOL COMPRISING AN ELONGATED BODY MEMBER OFGENERALLY TRIANGULAR CONFIGURATION VIEWED IN SIDE ELEVATION AND HAVINGOPPOSITELY EXTENDED DRIVING AND FULCRUM END PORTIONS, A DRIVING HEADDOWNWARDLY EXTENDED FROM THE DRIVING END PORTION AND HAVING ANDOWNWARDLY PRESENTED FACE, A FULCRUM DOWNWARDLY PRESENTED FROM THEFULCRUM END PORTION, AN UPWARDLY PRESENTED ANVIL PORTION INTERMEDIATETHE DRIVING AND FULCRUM ENDS, AND A WEB DOWNWARDLY EXTENDED TOWARD FROMTHE ANVIL PORTION TO A BASE EDGE AND EXTENDED TOWARD THE OPPOSITE ENDPORTIONS IN A TRIANGULAR CONFIGURATION IN SIDE ELEVATION, THE WEB ALSOBEING TRIANGULAR IN CROSS-SECTION IN A TRANSVERSE VERTICAL PLANE PASSINGTHROUGH THE ANVIL PORTION, THE TRIANGULAR CROSS-SECTION BEING OFINVERTED FORM AND TAPERING TOWARD THE BASE EDGE, AND AN UPWARDLYPRESENTED CLOSED HANDLE PORTION INTEGRALLY JOINED WITH THE BODY MEMBERAT A POINT ADJACENT TO THE FULCRUM END, THE DISTRIBUTION OF MASS OF THETOOL BEING SUCH TO LOCATE THE CENTER OF GRAVITY THEREOF WITHIN THE WEBAT A POINT INTERMEDIATE THE ANVIL PORTION AND THE FULCRUM END PORTION.